Suminina getmanovi (Ivachenko 1994) Late Permian, ~260 mya, 5.5 cm skull length, was a small basal therapsid famous for its "grasping" hands, making one of the first tree-dwelling vertebrates and the first one in the synapsid lineage. Distal carpal 1 was elongated (likely the product of fusion with the medial centrale which is otherwise absent). Suminia was basal to venjukoviamorphs like Venjukovia.
Distinct from Galechirus, Suminia had larger teeth, especially anteriorly. The cervicals were smaller, with lower neural spines. Fewer dorsals were present. The dorsal ribs were longer anteriorly, producing a deeper anterior thorax. The caudal chevrons were reduced to absent on the posterior 2/3 of the tail. The scapula was taller. The forearm was slightly longer. The fingers were relatively longer. Manual digit 4 included a disc-like phalanx (similar to Biarmosuschus). The ilium was expanded anteriorly and posteriolry. The femur was more robust. Pedal digit 1 was longer and, like the "thumb" may have been able to provide more a of a grasp by opposing digits 2-5. |
